The resistors are yellow-yellow-brown-gold.
Sounds like 440Ω ±5% all right, but 44 is not an E24 number
(or even E192 for that matter). I suppose that anything is possible, but I'd check them with an ohmmeter to make sure.
I did have a 10 uf cap on the other part of the board which may have still been connected across the + and -... I took everything off the board when things got wonky and all seems well now.
Not understanding where this cap was. Either on the 12V before the regulator or on the 5V after the regulator should be fine.
About the 8XAA, I'm just using it because it's convienent. I thought that the circuit wouldn't pull any more current through the VR than the circuit requires? I guess I'm misunderstanding some things.
You are understanding correctly. But it's just that much more voltage that the regulator has to drop. The power that the regulator has to dissipate is the voltage it has to drop (12 - 5 = 7V in this case) times the current through it. The current will be the same regardless of the input voltage, all other things being equal. So if the circuit draws 100mA at 5V, the regulator will dissipate 7V x 0.1A = 0.7W with 12V input and 4V x 100mA = 0.4W with 9V input. So a 3V increase in the input voltage results in a 75% increase in the power the regulator dissipates.
Thanks for the help! I'd like to figure this out so it won't happen again in the future!
Sure thing, hope you do!